A systematic comparison of deforestation drivers and policy effectiveness across the Amazon biome

Abstract

The Amazon biome, spanning nine countries, has one of the highest rates of deforestation worldwide. This deforestation contributes to biodiversity loss, climate change, the spread of infectious diseases, and damage to rural and indigenous livelihoods. Hundreds of articles have been published on the topic of deforestation across Amazonia, yet there has been no recent synthesis of deforestation drivers and deforestation-control policy effectiveness in the region. Here we undertook the first systematic review of papers published between 2000 to 2021 that have causally linked proximate and underlying drivers and policies to deforestation outcomes in Amazonia. In the 155 articles that met our inclusion criteria, we find that causal research is concentrated in Brazil, and to a lesser degree Peru, Ecuador, and Bolivia. There has been little study of the Guianas, Venezuela or Colombia. Large- and small-scale agriculture linked to improved market access and high agricultural prices are frequently researched proximate drivers of deforestation across the heavily researched regions. In the Guianas research focuses on mining with little focus on underlying causes. Research on infrastructure expansion, mining and oil extraction and on technological, sociocultural, and institutional factors remains sparse. Many public and private policies have been found to be effective in controlling deforestation across the biome, with protected areas standing out as particularly successful in slowing deforestation, vis-à-vis supply chain approaches. Our findings indicate a greater need for research on: i) additional deforestation drivers beyond agriculture and economic factors; ii) the complex interactions between different drivers and deforestation control policies; iii) causes underlying deforestation in low or new deforestation areas; and iv) the dynamics between Amazonian subregions and countries. Better understanding of all deforestation drivers and the effectiveness of existing deforestation mitigation policies is a prerequisite for completely halting deforestation in Amazonia.